1. Field of the Invention
The present invention generally relates to a digital video camera. More specifically, the present invention relates to a digital video camera in which an output from a CCD, for example, is converted into a digital signal so as to be processed in a digital manner.
2. Description of the Prior Art
Due to unevenness of a color filter of the CCD, there is an occasion that a subject is slightly colored with irregularity even when the subject is white. This can be solved by suppressing a low-saturation portion of a chrominance signal (modulated color signal). In a conventional analog camera signal processing circuit, a chrominance signal is subjected to a coring process, that is, a gain of the chrominance signal in the vicinity of zero is made small, and then the signal is filtered by a low-pass filter, whereby a low-saturation chrominance signal is suppressed.
In a signal processing for a video camera, a digital processing has an advantage over an analog processing for automating adjustment process, reduction of the number of parts, and etc. For handling a camera signal in a digital manner, the low-saturation chrominance suppression is, of course, to be performed in a digital signal processing. However, since a digital low-pass filter handles discreet values for processing the camera signal, if a signal processing similar to that of the analog processing is performed in the digital processing, a peak position of a signal after the digital low-pass filter becomes different from a peak position of a signal before the digital low-pass filter. That is, phases of the signals before and after the digital low-pass filter becomes different from each other, and resultingly, deviation occurs in hue of a chrominance signal being outputted (see FIG. 8).
In order to solve such hue deviation, a sampling frequency of the signal may be increased; however, it is not favorable that the sampling frequency is increased in a digital circuit because that causes increase of consumption electric power.